The aim is to provide the clinical and neuropsychological components needed to establish a model registry for patients with Alzheimer's disease. The program will support epidemiologic and clinical research activities by establishing criteria and standardized procedures for the diagnosis and characterization of this illness. At present, clinicians and scientists studying this disease utilize a variety of clinical measures and protocols, many of which are neither compatible nor suitable for coordinating multi-center research investigations. This project is designed as a consortium of physicians and scientists from Alzheimer's Disease Research Centers and other active research groups who will collaborate to achieve the following aims: (1) Establish simple and easily applicable criteria for the clinical and neyuropsychological diagnosis of Alzheimer's disease; (2) Develop standardized administration and scoring methods for assessing the presence and degree of dementia caused by Alzheimer's disease; (3) Establish procedures for training professional and technical personnel to conduct these specific tests and examinations; (4) Determine the reliability and validity of the clinical and neuropsychological procedures; (5) Build a model registry containing initial and follow-up data on patients with Alzheimer's disease. The procedures developed for the diagnosis of Alzheimer's disease will be suitable for cases identified by epidemiologic studies as well as those entering into medical care programs or enrolled in special research investigations.